Mitochondria–giant lipid droplet proximity and autophagy suppression in nitrogen-depleted oleaginous yeast Lipomyces starkeyi cells.

The article focuses on the interplay between mitochondria and lipid droplets (LDs) during giant LD formation in the oleaginous yeast Lipomyces starkeyi under nutrient starvation. It reports that under prolonged nitrogen starvation, mitochondria transition from fragmented forms to elongated tubules and sheet-like structures closely associated with a single giant LD, while mitochondrial degradation and autophagy are strongly suppressed. Conversely, carbon starvation suppresses mitochondrial elongation and LD expansion but induces mitochondrial degradation via autophagy, confirmed by suppression of mitophagy through overexpression of the autophagy-related protease LsAtg4. These findings suggest that giant LD formation in nitrogen-depleted L. starkeyi occurs independently of mitophagy and autophagy, highlighting a unique metabolic adaptation involving mitochondrial remodeling and organelle proximity.